Okamoto-Inoue M, Taniguchi S, Sadano H, Kawano T, Kimura G, Gabbiani G, Baba T
Department of Experimental Cell Research, Kyushu University, Fukuoka, Japan.
J Cell Sci. 1990 Aug;96 ( Pt 4):631-7. doi: 10.1242/jcs.96.4.631.
Expression of actin was examined in a cultured rat embryonic cell line 3Y1 and transformed cell lines that originated from 3Y1. An alpha-actin in addition to cytoplasmic beta- and gamma-actins was detected in 3Y1 by two-dimensional gel electrophoresis. This alpha-actin was hardly detected at all in the transformants induced by Rous sarcoma virus, v-H-ras oncogene or adenovirus type 12, while the alpha-actin was retained in the transformed cell lines induced by N-methyl-N'-nitro-N-nitrosoguanidine or in SV40, which are cell lines of relatively low malignancy. Western and Northern blot analyses established that this alpha-actin was a smooth muscle alpha-isoform. An immunofluorescence study revealed that smooth muscle alpha-actin in 3Y1 cells is present in stress fibers. Thus, smooth muscle alpha-actin is also a component of actin stress fibers, as beta- and gamma-actins are in 3Y1 cells. An alteration in the expression of this actin isoform may be related to phenotypical changes accompanying transformation.
在培养的大鼠胚胎细胞系3Y1以及源自3Y1的转化细胞系中检测了肌动蛋白的表达。通过二维凝胶电泳在3Y1中检测到除细胞质β-肌动蛋白和γ-肌动蛋白外的一种α-肌动蛋白。在劳氏肉瘤病毒、v-H-ras癌基因或12型腺病毒诱导的转化体中几乎完全检测不到这种α-肌动蛋白，而在由N-甲基-N'-硝基-N-亚硝基胍诱导的转化细胞系或SV40（恶性程度相对较低的细胞系）中保留了α-肌动蛋白。蛋白质免疫印迹和RNA印迹分析证实这种α-肌动蛋白是平滑肌α-同工型。免疫荧光研究显示3Y1细胞中的平滑肌α-肌动蛋白存在于应力纤维中。因此，平滑肌α-肌动蛋白也是肌动蛋白应力纤维的一个组成部分，就像β-肌动蛋白和γ-肌动蛋白在3Y1细胞中一样。这种肌动蛋白同工型表达的改变可能与转化伴随的表型变化有关。
